322
FXUS61 KBTV 120249
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
1049 PM EDT Fri Jul 11 2025
.SYNOPSIS...
Isolated showers and thunderstorms will diminish tonight, then
redevelop on Saturday as the region remains in a humid and
unstable pattern. A weak frontal passage will increase chances
for showers and thunderstorms later Sunday into Monday. Drier,
but continued hot and humid weather, is expected for the
remainder of next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 249 PM EDT Friday...For the rest of today, very isolated
pulse showers will continue with limited thunderstorm
development. They are primarily in northeastern/eastern Vermont
this afternoon, again, near and east of a weak and nearly
stationary surface front. Additionally, showers are developing
over the western Champlain Valley, likely driven by typical
differential heating/lake breeze convergence. The steering flow
will generally be to the southeast, especially when storms are
taller and tap into stronger winds aloft. With lack of upper
level forcing to help maintain instability driven by surface
heating, this activity should peak late afternoon trending
southward with time, and die off this evening. Convection will
not be strong enough to produce any significant impacts.
Some patchy fog overnight is probable with light winds and
seasonably humid air in place. That being said, mitigating factors
include organized upstream convection over the Midwest and the
associated mid and high level cloud cover that will stream across
the region. Low temperatures will mainly be in the 60s,
averaging about 5 to 10 degrees above normal.
Heat and humidity will build further for tomorrow as 850
millibar temperatures tick up a couple degrees amid weak ridging.
Confidence is moderate in maximum heat index values remaining a
touch below Heat Advisory criteria. Currently NBM guidance
suggests maximum heat index values in the low 90s are likely in
the Champlain Valley where light southerly low level flow will
minimize mixing of dry air aloft; think the HRRR tends to be
overmixed and its lower humidity is not realistic, while NAM3 as
typical is probably too extreme with depiction of low to mid 70
dew points during peak heating. High temperatures will range
through the 80s to near 90 in the warmest spots. Aside from the
heat, we will have to contend with thunderstorms again.
Precipitation potential, as noted by the previous forecaster,
has increased although coverage should remain isolated amid weak
forcing. There is high confidence in sufficient instability and
terrain driven lift to produce thunderstorms during the
afternoon, primarily near/just east of the highest terrain. That
being said, potential for severe weather remains low, as well,
with deep layer shear only 15 to 20 knots per mean HREF values.
Best overlap of CAPE and shear will tend to be over the
central/southern Green Mountains. Mean SB CAPE values will peak
in the 1500 to 2000 J/kg range. There is limited potential for
stronger convection given the high CAPE, which would be capable
of producing damaging wind/wet microbursts. Soundings show
substantial dry air entrainment with mid-level dry air to
suggest some potential in a rare storm that grows tall enough
for precipitation loading. PWAT will trend higher during the day
and become increasingly sufficient for heavy rainfall rates,
between the 75th and 90th climatological percentile when average
values rise into the 1.5 and 1.7 inch range.
For tomorrow night, an increasing pressure gradient and associated
low level jet of southerly winds will prevent fog formation and lead
to mild overnight conditions. Temperatures will be a few to
several degrees milder than tonight, in the mid 60s to low 70s.
&&
.SHORT TERM /SUNDAY NIGHT/...
As of 249 PM EDT Friday...Sunday continues to look like a
potential higher impact day for isolated severe weather and
flooding, with signals for this event being more likely in
northern New York than Vermont. We aren`t yet in the timeframe
to see the full suite of convective allowing models, but
generally the meteorological ingredients and limited CAM output
suggests potential for more linear/widespread convection with
this system, which would be oriented along a frontal boundary.
Additionally, machine learning convective hazard forecasts show
the northern Adirondacks having a local maximum for severe
thunderstorm probability. While there are chances for
thunderstorms Sunday afternoon/evening farther east, as we get
closer to the event would not be surprised if PoPs get peeled
back in eastern areas of the region; deep layer flow looks
southwesterly/parallel to the incoming surface front, which will
keep the eastward progress of showers and thunderstorms slow.
Heat and humidity looks similar to Saturday, with perhaps
slightly less heating due to more cloud cover. We also will see
substantially more wind than recent days, with a large scale
pattern where we will be squeezed between high pressure to our
east and seasonably strong low pressure tracking well to the
northwest near James Bay. Overnight the showers and thunderstorms
should diminish in intensity somewhat as they progress eastward,
while the surface front remains to our west through the night.
Another mild night with southerly flow is expected aside from
the showers and thunderstorms.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 217 PM EDT Friday...The slow-moving, stretched-out frontal
boundary coming in Monday will continue to track eastwards. The
better moisture plume from this coming Sunday will have shifted
east. Although there`s another shortwave and moisture plume, various
models disagree on the exact track of these secondary features. Some
scenarios track these more along the coastline and are more ill-
defined feature. Additionally, a warm layer aloft will suppress
thunderstorm development. However, by midday, there should be enough
instability to generate isolated to scattered shower and
thunderstorm activity across Vermont. The clouds and overhead
boundary will help conditions stay in the lower to mid 80s.
Default ridging and largely zonal flow aloft will allow temperatures
to trend higher again Tuesday and Wednesday with values flirting
with 90 again. A few ensemble members are hinting at a decaying MCS
type feature tracking across Canada that could just graze the region
late next Wednesday into Thursday. It seems a few showers and storms
could pop on the southern flank as it races east from James Bay
toward Quebec City. The larger scale system will arrive towards next
weekend with a deeper trough lifting northeast from the Great Lakes
region.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Through 00Z Sunday...Main aviation concern over the next 24
hours will be patchy fog and low stratus that will develop over
portions of the area. KBTV, KPBG, and KRUT will remain VFR over
the next 24 hours with light terrain driven winds. Have included
mention of fog or stratus at all other TAF sites, including
KSLK, KEFK, KMPV, and KMSS. Main timeframe for development of
low stratus and fog will be between 07Z and 11Z tonight, with
improvement to widespread VFR conditions expected by 12Z. During
the day Saturday, expect some isolated to scattered showers and
thunderstorms to develop, especially over our southern counties.
Outlook...
Saturday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Sunday: VFR. Chance SHRA, Chance TSRA.
Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA,
Chance TSRA.
Monday: Mainly VFR, with local IFR possible. Chance SHRA, Chance
TSRA.
Monday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Kutikoff
NEAR TERM...Kutikoff
SHORT TERM...Kutikoff
LONG TERM...Haynes
AVIATION...Duell
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